SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21c3a08ada61cbeb23d2982849b03eaa06321182fb1d4b77efe63c133a7b4577' 
  AND token = 'hLan8p5GavfmYGdN6ivJVtvyoYRxCholH+zAZHHjtz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}